1. Field of the Invention
The present invention relates to a resin molded article consisting of a plurality of members incorporated therein, more preferably, to a resin molded article eliminating the necessity of assembling steps and making it possible to easily obtain an appropriate clearance between the members.
2. Description of Prior Art
Equipment such as copying machines, printers, scanners or the like is structured by assembling many parts such as roller members for conveying sheets, gear members for transmitting driving force to the roller members, bearing members, and the like, and the parts to be used for the equipment are often constituted of resins.
In order to manufacture such a resin molded part, it is generally assumed that each of parts is first molded by injection molding or the like, and then two or more of the parts are assembled to constitute a unit. In the case of a gear unit, for example, a gear member and a bearing member are separately molded to be assembled together, and further a slip stopper is attached thereto for preventing those parts from slipping. In the case of a bearing unit, an outer ring, an inner ring, roller members to be arranged between the both rings, or the like are first molded, and then those are assembled to constitute a unit.
Such a conventional manner, however, requires a step of manufacturing independently a plurality of parts and then engagingly assembling those parts, which has become a factor in increasing costs.
In addition, when a plurality of parts were assembled, especially in the case of rotary members such as rollers, gears or the like, a clearance between the members was required to be controlled with accuracy, but measurement errors easily occured at the time of manufacturing independently a plurality of the parts. Therefore, maintaining control with accuracy was not easy.
The present invention was accomplished in view of the aforementioned conventional problems, and an object of the present invention is to provide a resin molded article that eliminates a step of independently manufacturing a plurality of parts and assembling them and that facilitates the control of a clearance between the members at a low cost.
In order to accomplish the aforementioned object, a representative structure according to the present invention is so constituted that at least a first resin material and a second resin material, which are substantially insoluble (having substantially no compatibility) in one another are used and molded by insert molding or two-color molding, in a state where the first resin material and the second resin material are incorporated, and a clearance is produced between the first member and the second member.
In the structure as mentioned above, since there is substantially insolubility between the first member and the second member, each of the plural members, molded by insert molding or two-color molding, is to be separated in a state of being assembled. This, therefore, eliminates the necessity of steps for assembling a plural number of parts. In addition, by making a mold shrinkage factor differ between the first resin material and the second resin material, a clearance between the members can be controlled easily and with good accuracy.
Thus, a bearing part, roller part or drive unit, which is constituted of incorporated plural members, can be easily manufactured.